Food cooked with plastic wrap

Do you notice that more and more food manufacturers prepare their food products using plastic materials? Pls help identify them: 

• 1. Dumplings (棕子）wrapped with plastic strings and boiled for hours: 
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• 2. Smoked ham wrapped in plastic sheet and smoked/heated for days 
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• 3. Some dim sum covered with plastic film and steamed for hours 
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• 4. Satay and lotong rice are cooked in plastic tube, not with coconut leaves as usual

Budha Jumps Over the Wall, but wrapped and cooked for 8 to 12 hours